To learn kicks I took Tae Kwon Do. I learned to see how a kick begins and the destruction that a kick can do. You learn to be very appreciative of the quickness and effectiveness from a kick. I took it for 1 1/2 years before I got my shodan in aikido.
I don't believe that kicks should be a contant training portion of aikido. Sure, we do have classes about once a month covering kicks, but the kicks that an aikidoko throw are nothing compared to a skilled Tae Kwon Do practicioner. Of course, the chances of a street fighter throwing kicks like a TKD martial artist is also slim to none.
I think that in aikido it more important to learn to take your uke's balance. Once you truly learn this - then a kick is like a punch. Don't focus on the kick, focus on the uke's center. It has worked for me. I have tried it with my fellow TKD practioners.